The gene's association with schizophrenia was also confirmed by a global study, which studied the genomes of 36,989 people with schizophrenia and 113,075 healthy subjects across the world.

Doctor David Curtis, a Professor of psychiatry, said: "We could be looking at the next big drug target for treating mental illness.

"The work opens up new ways to prevent and treat mental illnesses by revealing the mechanisms involved in their development. The result for GRM3 from the consortium is particularly compelling, as the odds of this occurring by chance are only one in a billion."

Present treatment for schizophrenia involves drugs that reduce the activity of the chemical dopamine, which is involved in the transmission of messages between brain cells.

Over-active dopamine signalling may cause unwanted communication between parts of the brain designed to be separate, such as signalling between the speech and hearing centres of the brain, causing schizophrenics to 'hear voices'.

However, scientists have found communication between brain cells depends on a number of other chemicals, including glutamate, whose production is controlled by the GRM3 gene.

Dr Andrew McQuillin, head of the UCL Molecular Psychiatry team that first discovered GRM3 said: "Drug treatments for schizophrenia have barely changed over the past few decades, as they still target dopamine receptors.

Schizophrenia treatments targeting glutamate receptors have been tested in the past without success. However, they might be more effective at treating patient groups with mutations in glutamate receptors such as GRM3."